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Future fusion reactors must be able to breed the tritium they will consume. Several breeding and tritium extraction technologies are under investigation internationally. PbLi is of particular inter...

Permeation is investigated for the introduction of hydrogen isotopes into lead lithium (PbLi) for the Tritium Extraction eXperiment (TEX). TEX is a forced-convection PbLi loop under construction at Idaho National Laboratory that will test the vacuum permeator (VP) method of tritium extraction from PbLi. The source permeator (SP) delivers atomic hydrogen (H, D, and T) from a gas-phase reservoir into the PbLi via a permeable dense metal membrane. A modular system and a fixed SP system are presented. In the modular design, PbLi flows through the inside of a tubular membrane, and gas-phase hydrogen is introduced on the outside of the membrane. Atomic hydrogen permeates radially inward through the membrane into the PbLi. In the fixed design, PbLi flows into an expansion chamber with closed-ended tubular membranes inserted. Gas-phase hydrogen is introduced on the inside of the closed-ended membranes, and atomic hydrogen permeates radially outward into the flowing PbLi. Hydrogen transport models based on steady-state mass transport through PbLi and permeation through the metal membrane were developed to assess the operation of the SP relative to experimental variables and to allow understanding of uncertain parameter effects, such as PbLi hydrogen transport properties and the effective hydrogen permeability of the VP. This modeling effort considers iron as the SP material and vanadium as the VP material.

Objective This study sought to determine if there was a difference in the months of oral contraception prescribed by resident physicians living in U.S. states with a 12-month supply policy compared to resident physicians in states without a policy. Methods We conducted an exploratory descriptive study using a convenience sample of Obstetrics and Gynecology resident physicians (n = 275) in the United States. Standard bivariate analyses were used to compare the difference between groups. Results Few resident physicians in both groups (3.8% with a policy and 1.4% without a policy) routinely prescribed a 12-month supply of contraception. The mean coverage prescribed by providers in states with and without a policy was 2.81 and 2.07 months (p Conclusions The majority of resident physicians were unaware of 12-month contraceptive supply policies and unable to correctly write a prescription for 12-months of contraception, regardless of whether they lived in a state with a 12-month contraceptive supply policy. Physician education may be needed to effectively implement 12-month contraceptive supply policies.

Most ULXs are believed to be powered by super-Eddington accreting neutron stars and, perhaps, black holes. Above the Eddington rate the disc is expected to thicken and to launch powerful winds through radiation pressure. Winds have been recently discovered in several ULXs. However, it is yet unclear whether the thickening of the disc or the wind variability causes the switch between the classical soft and supersoft states observed in some ULXs. In order to understand such phenomenology and the overall super-Eddington mechanism, we undertook a large (800 ks) observing campaign with XMM-Newton to study NGC 247 ULX-1, which shifts between a supersoft and classical soft ULX state. The new observations show unambiguous evidence of a wind in the form of emission and absorption lines from highly-ionised ionic species, with the latter indicating a mildly-relativistic outflow (-0.17c) in line with the detections in other ULXs. Strong dipping activity is observed in the lightcurve and primarily during the brightest observations, which is typical among soft ULXs, and indicates a close relationship between the accretion rate and the appearance of the dips. The latter is likely due to a thickening of the disc scale-height and the wind as shown by a progressively increasing blueshift in the spectral lines., 18 pages, 16 figures, accepted for publication in MNRAS

Liquid ammonia is a high-density (17.7 wt %) hydrogen carrier with a well-established production and distribution infrastructure. Efficient decomposition and purification are essential for its use ...

Transition metal carbide coated vanadium membranes for hydrogen permeation have the unique ability to operate at both high temperatures and pressures. Titanium carbide deposited by magnetron sputte...

Mo2C has previously been demonstrated as an effective catalyst layer to enable stable H2 permeation through vanadium foils at high temperatures. In this study, this approach was extended to several group V metal foils (V, Nb, and Ta) as well as mixed gas testing. The best permeability was achieved with V, and an activation process was developed to recover the performance of V foils displaying evidence of oxidation. Nb foils yielded ~ 20% the permeability of V, while Ta was too brittle to operate effectively. Mo2C/V membranes were operated at feed conditions well above the ductile-to-brittle transition pressure without embrittlement; however, the H2 permeability of Mo2C/V membranes was significantly attenuated at lower temperatures (

A grand challenge of vanadium-based H2 permeable membranes is the development of effective, cheap, and stable catalysts to facilitate H2 dissociation and recombination. This work investigates a fac...

In this work, we discuss an observed reduction of magnesium from a MgO/MgAl 2 O 4 ceramic substrate by permeating hydrogen in thin-film Pd membranes. Membranes were fabricated via electroless plating of Pd on a porous MgO/MgAl 2 O 4 substrate and tested under pure hydrogen permeation conditions between 500 °C and 700 °C. It was observed that a rapid and severe hydrogen flux decline occurred at 700 °C, whereat up to 96% of the hydrogen flux was lost within 40 h of operation. Using energy dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy, it was concluded that the flux loss occurred due to alloying and a subsequent surface segregation of Mg in the Pd film. In contrast, a control test in which the membrane was soaked in hydrogen at 700 °C without permeation resulted in only very slight or potentially no MgO reduction or alloying with the Pd. The significantly enhanced reduction of MgO/MgAl 2 O 4 during membrane operation is attributed to the chemical potential provided by atomic hydrogen permeating through the membrane.

The effects of high pressure gas exposure on the hydrogen flux though Pd films were explored. It was observed that exposure of a Pd membrane to N 2 , Ar, or CO 2 at 3.0 MPa and 500 °C caused a substantial decline in hydrogen flux within 24 h that only recovered to ca. 60% of its initial value after 24 h of subsequent hydrogen exposure. Atomic force microscopy images revealed that the Pd surface became smoother with a reduction in density of nanoscale features after high pressure exposure, consistent with an observed transition in rate limiting step from bulk diffusion to surface kinetics. The rate of flux loss was found to have an apparent activation energy of 39 kJ mol −1 , which is consistent with values reported for Pd surface self-diffusion. This effect was not observed when the exposure gas was helium or at pressures 2 impurities (ca. 1%) in the feed.

A new combined positron annihilation lifetime spectroscopy (PALS) and coincidence Doppler broadening (CDB) system has been constructed at Idaho National Laboratory (INL). The design and commissioning process are discussed with practical guidelines that can be followed for the installation of new systems. In addition, the new system was used to investigate defect structure in titanium and titanium deuteride samples where the deuterium concentration ranges from 0.10 to 2 x 10−5. The TiD samples were found to be largely defect free based on the positron lifetimes and S- W curves. Ratio curves of the CDB spectra showed elemental sensitivity to the deuterium in the samples, that increased with deuterium concentration.

Dense vanadium-based membranes offer high permeability and perfect selectivity to hydrogen isotopes, maintain favorable neutronic properties, and are compatible with liquid metals such as PbLi. These properties make vanadium membranes a promising fusion fuel cycle technology for processes such as tritium extraction from PbLi and exhaust processing. Surface contamination has a deleterious effect on the gas-phase hydrogen permeation through vanadium, and the reported permeabilities range from 10-14 to 10-7 mol m-1 s-1 Pa-0.5. Thin dense films of palladium applied to clean vanadium surfaces enable a consistently high hydrogen permeability. In this study, uncoated vanadium resulted in deuterium permeabilities ranging from 2.8 × 10-11 to 6.4 × 10-9 mol m-1 s-1 Pa-0.5 at 300 °C–700 °C, respectively. Post-test analysis revealed a VOx surface layer and VCx subsurface layer formed on the feed side, while the as-received surface oxide dissolved leaving a submonolayer oxide on the permeate surface. The Pd-coated V resulted in a maximum deuterium permeability of 2.1 × 10-7 mol m-1 s-1 Pa-0.5 at 375 °C upon activation of the Pd surface by oxidation and reduction. The deuterium permeation declined upon heating to 500 °C due to intermetallic diffusion between the Pd and V. The Mo2C-coated V resulted in deuterium permeabilities ranging from 2.7 × 10-10 to 1.8 × 10-9 at 500 °C–700 °C, respectively, and a post-test analysis found the carbon in the Mo2C layer had dissolved into the V near the interface.

High-performance lithium-ion batteries require electrolytes that are stable over wide operating voltages. We used density functional theory to investigate the degradation of ethylene carbonate (EC) electrolytes activated by interactions with LiCoO2 cathode surfaces and PF5 species in the electrolyte. We report detailed mechanisms for the activation of EC ring-opening reactions by Lewis acids to form CO2, organics, or organofluorines. We find that Lewis acid–base complexation between EC and either PF5 or LiCoO2 weakens the C–O bonds of the EC ring and consequently lowers the barrier to and energy of EC ring-opening reactions. Our results predict that ring opening activated by the LiCoO2 cathode surface forms a cathode–electrolyte interphase primarily composed of an organic and organofluorine film. Simultaneous degradation of an EC molecule and PF6– forms PF5 and a surface organofluorine with an activation barrier of 1.28 eV and reaction energy of −0.26 eV. Ring opening of EC activated by the cathode to for...

We present simultaneous XMM-Newton and NuSTAR observations spanning 3-78 keV of the nearest radio galaxy, Centaurus A (Cen A). The accretion geometry around the central engine in Cen A is still debated, and we investigate possible configurations using detailed X-ray spectral modeling. NuSTAR imaged the central region of Cen A with sub-arcminute resolution at X-ray energies above 10 keV for the first time, but finds no evidence for an extended source or other off-nuclear point-sources. The XMM-Newton and NuSTAR spectra agree well and can be described with an absorbed power-law with a photon index {\Gamma} = 1.815 +/- 0.005 and a fluorescent Fe K{\alpha} line in good agreement with literature values. The spectrum does not require a high-energy exponential rollover, with a constraint of E_fold > 1 MeV. A thermal Comptonization continuum describes the data well, with parameters that agree with values measured by INTEGRAL, in particular an electron temperature kTe between ~100-300 keV, seed photon input temperatures between 5-50 eV. We do not find evidence for reflection or a broad iron line and put stringent upper limits of R < 0.01 on the reflection fraction and accretion disk illumination. We use archival Chandra data to estimate the contribution from diffuse emission, extra-nuclear point-sources, and the outer X-ray jet to the observed NuSTAR and XMM-Newton X-ray spectra and find the contribution to be negligible. We discuss different scenarios for the physical origin of the observed hard X-ray spectrum, and conclude that the inner disk is replaced by an advection-dominated accretion flow or that the X-rays are dominated by synchrotron self-Compton emission from the inner regions of the radio jet or a combination thereof., Comment: 13 pages, 6 figures, accepted for publication in ApJ

The effects of gold concentration on the carbon tolerance of palladium-based composite membranes was studied under the presence of high CO concentrations. Membranes with PdAu compositions up to 41% Au by mass were exposed to 50/50H2/CO gas atmospheres and both hydrogen flux and permeate purity were monitored over time. The highest gold concentration (41 wt%) had no measurable degradation in membrane performance in terms of either hydrogen permeate purity or hydrogen permeation flux during the 48 h exposure; in contrast, the pure palladium membrane suffered total degradation during the same exposure time. Furthermore, for lower gold concentrations, X-ray diffraction patterns suggested that carbon entered the membrane film and could be removed by exposure to hydrogen and a non-CO containing gas mixture over time; however, removal of the carbon adversely affected hydrogen permeate purity. Interestingly, some of the observed hydrogen permeate purity decline could be reversed upon re-exposure to the CO gas mixture. It is hypothesized that carbon loading in the palladium films causes lattice expansion and may even fill pore defects, thus lowering non-hydrogen leaks through the Pd membrane films. This study suggests that a membrane exposed to a CO mixture should not be cycled between CO and non-CO environments, but rather run continuously for best performance. Additionally, the choice of Pd-alloy metal and composition should be considered in regard to its carbon solubility to best predict lifetime performance.

We utilized density functional theory to examine HF generation in lithium-ion battery electrolytes from reactions between H2O and the decomposition products of three electrolyte additives: LiPF6, LiPOF4, and LiAsF6. Decomposition of these additives produces PF5, AsF5, and POF3 along with LiF precipitates. We found PF5 and AsF5 react with H2O in two sequential steps to form two HF molecules and POF3 and AsOF3, respectively. PF5 (or AsF5) complexes with H2O and undergoes ligand exchange to form HF and PF4OH (AsF4OH) with an activation barrier of 114.2 (30.5) kJ mol−1 and reaction enthalpy of 14.6 (−11.3) kJ mol−1. The ethylene carbonate (EC) electrolyte forms a Lewis acid–base complex with the PF4OH (AsF4OH) product, reducing the barrier to HF formation. Reactions of POF3 were examined and are not characterized by complexation of POF3 with H2O or EC, while PF5 and AsF5 complex favorably with H2O and EC. HF formation from POF3 occurs with a reaction enthalpy of −3.8 kJ mol−1 and a 157.7 kJ mol−1 barrier, 43.5 kJ mol−1 higher than forming HF from PF5. HF generation in electrolytes employing LiPOF4 should be significantly lower than those using LiPF6 or LiAsF6 and LiPOF4 should be further investigated as an alternative electrolyte additive.

The design, fabrication, and evaluation of flexible, multilayer optical coatings deposited by plasma-enhanced chemical vapor deposition at low temperature are demonstrated using hybrid nanolaminates consisting of TiO2 and silicone (SiOxCyHz) as the high and low refractive index materials, respectively. A broadband anti-reflection coating was designed and deposited onto a variety of substrates including flexible polyethylene terephthalate (PET) and CdTe solar cells which was shown to increase absolute transmission by an average of 3% over 410–850 nm wavelengths and results in a commensurate increase in short circuit current density. An infrared reflector was designed and applied to PET which was found to provide 70% reflectance in the near-IR while maintaining >80% transmittance for visible light. The optical performance of these flexible coatings on PET remained unchanged after automated bend testing, and were shown to be robust with respect to humidity and thermal shock tests.

We utilized density functional theory (DFT) to systematically investigate the ability of B, C, and N interstitial and O substitutional surface and near-surface dopants in TiO2 to facilitate O2 reduction and adsorption. Periodic boundary condition calculations based on the PBE+U DFT functional show that dopants that create filled band gap states with energies higher than that of the near surface O2 πz* molecular orbital enable O2 adsorption and reduction. Sites that create unoccupied band gap states with energies below that of the O2 πz* orbital reduce TiO2’s reduction ability as these states result in photoexcited electrons with insufficient reduction potential to reduce O2. B dopants in interstitial and relaxed substitutional sites, whose gap states lie >1.5 eV above the valence band maximum (VBM) and hence above O2’s πz* level, facilitate the reduction of O2 to the peroxide state with adsorption energies on TiO2 of −1.22 to −2.77 eV. However, N dopants, whose gap states lie less than ∼1 eV above the VBM...

We present a broad band spectral analysis of the joint XMM-Newton and NuSTAR observational campaign of the Narrow Line Seyfert 1 SWIFT J2127.4+5654, consisting of 300 ks performed during three XMM-Newton orbits. We detect a relativistic broadened iron K$\alpha$ line originating from the innermost regions of the accretion disc surrounding the central black hole, from which we infer an intermediate spin of $a$=$0.58^{+0.11}_{-0.17}$. The intrinsic spectrum is steep ($\Gamma=2.08\pm0.01$) as commonly found in Narrow Line Seyfert 1 galaxies, while the cutoff energy (E$_{\rm c}=108^{+11}_{-10}$ keV) falls within the range observed in Broad Line Seyfert 1 Galaxies. We measure a low-frequency lag that increases steadily with energy, while at high frequencies, there is a clear lag following the shape of the broad Fe K emission line. Interestingly, the observed Fe K lag in SWIFT J2127.4+5654 is not as broad as in other sources that have maximally spinning black holes. The lag amplitude suggests a continuum-to-reprocessor distance of about $ 10-20\ r_{\mathrm{g}}$. These timing results independently support an intermediate black hole spin and a compact corona., Comment: 11 pages, 10 figures, accepted for publication on MNRAS

The current technology for hydrogen isotope separation requires enormous capital investment and energy consumption. Palladium-based membranes exhibit hydrogen isotope selectivity and provide a continuous method of isotope enrichment but have high material costs. Here, the authors investigate the potential of titanium carbide thin films coated on vanadium as a low-cost alternative, which enabled operation at high temperatures. Protium and deuterium exhibited nominally identical solubility in TiC coated vanadium over a range of 500–700 °C. Permeation tests from 600 to 700 °C revealed that protium permeated faster than deuterium, with the separation factor decreasing from 1.34 to 1.15 with increasing temperature. XPS depth-profiling showed a distinct interface between the TiC layer and the V foil in as-fabricated membranes. However, post-test analysis revealed significant V diffusion through TiC and segregation to the surface. Surface limitations resulting from this degradation accounted for changes in flux and may explain why the separation factor was lower than the value of 1.42 expected from high temperature interstitial diffusion of protium/deuterium in vanadium.The current technology for hydrogen isotope separation requires enormous capital investment and energy consumption. Palladium-based membranes exhibit hydrogen isotope selectivity and provide a continuous method of isotope enrichment but have high material costs. Here, the authors investigate the potential of titanium carbide thin films coated on vanadium as a low-cost alternative, which enabled operation at high temperatures. Protium and deuterium exhibited nominally identical solubility in TiC coated vanadium over a range of 500–700 °C. Permeation tests from 600 to 700 °C revealed that protium permeated faster than deuterium, with the separation factor decreasing from 1.34 to 1.15 with increasing temperature. XPS depth-profiling showed a distinct interface between the TiC layer and the V foil in as-fabricated membranes. However, post-test analysis revealed significant V diffusion through TiC and segregation to the surface. Surface limitations resulting from this degradation accounted for changes in flux ...

High-performance lithium-ion batteries require electrolytes that are stable over wide operating voltages. We used density functional theory to investigate the degradation of ethylene carbonate (EC) electrolytes activated by interactions with LiCoO

We present the results from coordinated X-ray observations of the ultraluminous X-ray source NGC 5204 X-1 performed by NuSTAR and XMM-Newton in early 2013. These observations provide the first detection of NGC 5204 X-1 above 10 keV, extending the broadband coverage to 0.3-20 keV. The observations were carried out in two epochs separated by approximately 10 days, and showed little spectral variation, with an observed luminosity of Lx = (4.95+/-0.11)e39 erg/s. The broadband spectrum confirms the presence of a clear spectral downturn above 10 keV seen in some previous observations. This cutoff is inconsistent with the standard low/hard state seen in Galactic black hole binaries, as would be expected from an intermediate mass black hole accreting at significantly sub-Eddington rates given the observed luminosity. The continuum is apparently dominated by two optically thick thermal-like components, potentially accompanied by a faint high energy tail. The broadband spectrum is likely associated with an accretion disk that differs from a standard Shakura & Sunyaev thin disk., 7 pages, 5 figures. Accepted for publication in ApJ

We present simultaneous XMM-Newton and NuSTAR observations of the `bare' Seyfert 1 galaxy, Ark 120, a system in which ionized absorption is absent. The NuSTAR hard X-ray spectral coverage allows us to constrain different models for the excess soft X-ray emission. Among phenomenological models, a cutoff power law best explains the soft X-ray emission. This model likely corresponds to Comptonization of the accretion disk seed UV photons by a population of warm electrons: using Comptonization models, a temperature of ~0.3 keV and an optical depth of ~13 are found. If the UV-to-X-ray optxagnf model is applied, the UV fluxes from the XMM-$Newton$ Optical Monitor suggest an intermediate black hole spin. Contrary to several other sources observed by NuSTAR, no high energy cutoff is detected, with a lower limit of 190 keV., Comment: 6 pages. Accepted for publication in MNRAS

We present a timing and spectral analysis of the variable X-ray source 3A 1954+319. Our analysis is mainly based on an outburst serendipitously observed during INTEGRAL Key Program observations of the Cygnus region in 2008 fall and on the Swift/BAT longterm light curve. Previous observations, though sparse, have identified the source to be one of only nine known symbiotic X-ray binaries, i.e., systems composed of an accreting neutron star orbiting in a highly inhomogeneous medium around an M-giant companion. The spectrum of 3A 1954+319 above 20 keV can be best described by a broken power law model. The extremely long pulse period of ~5.3 hours is clearly visible in the INTEGRAL/ISGRI light curve and confirmed through an epoch folding period search. Furthermore, the light curve allows us to determine a very strong spin up of -2x10^-4 h/h during the outburst. This spin up is confirmed by the pulse period evolution calculated from Swift/BAT data. The Swift/BAT data also show a long spin-down trend prior to the 2008 outburst, which is confirmed in archival INTEGRAL/ISGRI data. We discuss possible accretion models and geometries allowing for the transfer of such large amounts of angular momentum and investigate the harder spectrum of this outburst compared to previously published results., 6 pages, 3 figures; published online as PoS(INTEGRAL 2010)017, Proceedings of the 8th INTEGRAL Workshop "The Restless Gamma-ray Universe", September 27-30, 2010, Dublin, Ireland

We present spectral analysis of five NuSTAR and Swift observations of GX 339-4 taken during a failed outburst in summer 2013. These observations cover Eddington luminosity fractions in the range ~0.9-6%. Throughout this outburst, GX 339-4 stayed in the hard state, and all five observations show similar X-ray spectra with a hard power-law with a photon index near 1.6 and significant contribution from reflection. Using simple reflection models we find unrealistically high iron abundances. Allowing for different photon indices for the continuum incident on the reflector relative to the underlying observed continuum results in a statistically better fit and reduced iron abundances. With a photon index around 1.3, the input power-law on the reflector is significantly harder than that which is directly observed. We study the influence of different emissivity profiles and geometries and consistently find an improvement when using separate photon indices. The inferred inner accretion disk radius is strongly model dependent, but we do not find evidence for a truncation radius larger than 100 r_g in any model. The data do not allow independent spin constraints but the results are consistent with the literature (i.e., a>0). Our best-fit models indicate an inclination angle in the range 40-60 degrees, consistent with limits on the orbital inclination but higher than reported in the literature using standard reflection models. The iron line around 6.4 keV is clearly broadened, and we detect a superimposed narrow core as well. This core originates from a fluorescence region outside the influence of the strong gravity of the black hole and we discuss possible geometries., 11 pages, 6 figures, 6 tables, plus 9 tables in the appendix. Submitted to ApJ

We present simultaneous Nuclear Spectroscopic Telescope Array (NuSTAR ) and Suzaku observations of the X-ray binary Cygnus X-1 in the hard state. This is the first time this state has been observed in Cyg X-1 with NuSTAR, which enables us to study the reflection and broad-band spectra in unprecedented detail. We confirm that the iron line cannot be fit with a combination of narrow lines and absorption features, and instead requires a relativistically blurred profile in combination with a narrow line and absorption from the companion wind. We use the reflection models of Garcia et al. (2014) to simultaneously measure the black hole spin, disk inner radius, and coronal height in a self-consistent manner. Detailed fits to the iron line profile indicate a high level of relativistic blurring, indicative of reflection from the inner accretion disk. We find a high spin, a small inner disk radius, and a low source height, and rule out truncation to greater than three gravitational radii at the 3{\sigma} confidence level. In addition, we find that the line profile has not changed greatly in the switch from soft to hard states, and that the differences are consistent with changes in the underlying reflection spectrum rather than the relativistic blurring. We find that the blurring parameters are consistent when fitting either just the iron line or the entire broad-band spectrum, which is well modelled with a Comptonized continuum plus reflection model., Comment: 12 pages, 7 figures, accepted for publication in ApJ

The Circinus galaxy is one of the nearest obscured AGN, making it an ideal target for detailed study. Combining archival Chandra and XMM-Newton data with new NuSTAR observations, we model the 2-79 keV spectrum to constrain the primary AGN continuum and to derive physical parameters for the obscuring material. Chandra's high angular resolution allows a separation of nuclear and off-nuclear galactic emission. In the off-nuclear diffuse emission we find signatures of strong cold reflection, including high equivalent-width neutral Fe lines. This Compton-scattered off-nuclear emission amounts to 18% of the nuclear flux in the Fe line region, but becomes comparable to the nuclear emission above 30 keV. The new analysis no longer supports a prominent transmitted AGN component in the observed band. We find that the nuclear spectrum is consistent with Compton-scattering by an optically-thick torus, where the intrinsic spectrum is a powerlaw of photon index $\Gamma = 2.2-2.4$, the torus has an equatorial column density of $N_{\rm H} = (6-10)\times10^{24}$cm$^{-2}$ and the intrinsic AGN $2-10$ keV luminosity is $(2.3-5.1)\times 10^{42}$ erg/s. These values place Circinus along the same relations as unobscured AGN in accretion rate-vs-$\Gamma$ and $L_X$-vs-$L_{IR}$ phase space. NuSTAR's high sensitivity and low background allow us to study the short time-scale variability of Circinus at X-ray energies above 10 keV for the first time. The lack of detected variability favors a Compton-thick absorber, in line with the the spectral fitting results.

This study compared the marginal microleakage of Class V cavities restored with Dyract-AP and F2000. Forty Class V cavity preparations were performed on extracted human teeth. As a negative control, twenty teeth were used without Class V preparations. The apical foramina of the teeth were sealed with a layer of varnish and amalgam restorations. Class V cavity preparations with occlusal margins in enamel, and gingival margins in cementum or dentin that measured approximately three millimeters in width (gingival-occlusal) and length (mesial-distal), were prepared on the buccal surface of the teeth. Samples were divided randomly into 2 groups of 15, and restored per manufacturer's instructions using experimental primer/conditioner (PCC, D/C) and Single Bond Adhesive (3M). All restorations were polished with an abrasive finishing kit. After storage in 37 degrees C water for 24 hours, all specimens were thermocycled between 5 degrees C and 55 degrees C for 500 cycles with a 30-second dwell time, followed by immersion in 0.2% basic fucsine for 24 hours. Teeth were then embedded in cold cure acrylic resin, sectioned longitudinally, and the dye penetration at the enamel and cementum margins were scored at 30x magnification. Evaluations were rated from 0 to 3 (0 = no leakage; 1 = dye penetration up to one-half of the preparation depth; 2 = dye penetration more than one-half preparation depth, but less than the axial wall; 3 = dye penetration along the axial wall). Both F-2000 and Dyract-AP indicated no leakage in the enamel margins. Dyract-AP showed no leakage at either the enamel or dentin margins. Fisher's Exact Test revealed that this difference in dentin margins was statistically significant (p0.05). Under the given conditions, Dyract-AP and F-2000 demonstrated resistance to microleakage in enamel, and showed Dyract-AP to be more resistant to microleakage in dentin than F-2000.

THE broad generalization has been established that the fowl has a sense of taste. An extensive discussion of the subject is offered by Engelmann (1957). The effect of taste on feed and fluid intake has been reported by Kare and Pick (1960). Further elucidation of this subject appears warranted. A series of experiments was designed to determine if chicks will discriminate between acid and alkaline solutions and to define, precisely, the influence of pH on acceptance, rejection, or preference. MATERIALS AND METHODS These experiments were conducted using the methods described by Kare et al. (1957). They were carried out in a special building where the environment was kept relatively constant. Light was provided from 6:00 a.m. to 8:00 p.m. Barred Plymouth Rock-Rhode Island Red cross-bred day-old cockerels from a single hatchery were used. Sixteen chicks per pen for the first eight experiments and thereafter ten chicks per pen were placed …

A double-blind parallel study comparing tolnaftate cream with undecylenic acid ointment and a placebo ointment in the treatment of symptomatic tinea pedis was conducted on the warm, humid Texas Gulf Coast. In one hundred and three patients studied, both the clinical and mycological effects of the two antifungal agents were indistinguishable. Both were significantly more effective than the placebo.

We present an analysis of NuSTAR observations of a hard intermediate state of the transient black hole GX 339-4 taken in January 2015. As the source softened significantly over the course of the 1.3 d-long observation we split the data into 21 sub-sets and find that the spectrum of all of them can be well described by a power-law continuum with an additional relativistically blurred reflection component. The photon index increases from ~1.69 to ~1.77 over the course of the observation. The accretion disk is truncated at around 9 gravitational radii in all spectra. We also perform timing analysis on the same 21 individual data sets, and find a strong type-C quasi-periodic oscillation (QPO), which increase in frequency from ~0.68 to ~1.05 Hz with time. The frequency change is well correlated with the softening of the spectrum. We discuss possible scenarios for the production of the QPO and calculate predicted inner radii in the relativistic precession model as well as the global disk mode oscillations model. We find discrepancies with respect to the observed values in both models unless we allow for a black hole mass of ~100 M_sun , which is highly unlikely. We discuss possible systematic uncertainties, in particular with the measurement of the inner accretion disk radius in the relativistic reflection model. We conclude that the combination of observed QPO frequencies and inner accretion disk radii, as obtained from spectral fitting, is difficult to reconcile with current models., Comment: 10 pages, 8 figures; accepted for publication in ApJ

Electron cyclotron resonant scattering features (CRSFs) are observed as absorption-like lines in the spectra of X-ray pulsars. A significant fraction of the computing time for Monte Carlo simulations of these quantum mechanical features is spent on the calculation of the mean free path for each individual photon before scattering, since it involves a complex numerical integration over the scattering cross section and the (thermal) velocity distribution of the scattering electrons. We aim to numerically calculate interpolation tables which can be used in CRSF simulations to sample the mean free path of the scattering photon and the momentum of the scattering electron. The tables also contain all the information required for sampling the scattering electron's final spin. The tables were calculated using an adaptive Simpson integration scheme. The energy and angle grids were refined until a prescribed accuracy is reached. The tables are used by our simulation code to produce artificial CRSF spectra. The electron momenta sampled during these simulations were analyzed and justified using theoretically determined boundaries. We present a complete set of tables suited for mean free path calculations of Monte Carlo simulations of the cyclotron scattering process for conditions expected in typical X-ray pulsar accretion columns (0.01, Comment: A&A, in press